Valveless hydraulic apparatus



Oct. 28. 1924.

E. M. SMITH ELEss HYDRAULIC APPARATUS VALV Filed May 19 1922 2 Sheets-Sheet 1 Oct. 28.1924. v n1,513,564

' E. M. SMITH vALvELEss HYDRAULIc APPARATUS Filed Hay 19, 1922 2 Sheets-Sheet 2 3 l C V C/ M F/a. 2 AEZ D Patented Oct. 28, 1924.

UNITED ERIC IVIONTAGUE SMITH,

or sALrronn, ENGLAND.

Application filled May 19.

To all whom t may concern.'

Be it known that I, Euro MONTAGUE SMITH, residing at Keynsham Manor, Saltford, in the county of Somerset, England, a subjrect of the King of Great Brit-ain, have invented certainnew and useful lImprovements in or Relating to Valveless Hydraulic Apparatus, of which the following is a specification.

This invention refers to improvements in valveless hydraulic apparatus or presses applicable for use in connection with various apparatus such as, for example, metal punching, shearing or cropping machines or the like wherein hydraulic pressure is employed to act in conjunction with and to `Aam lify mechanically obtained pressure;

an one of the objects kof my present invention is to provide an improved and simplified apparatus in which, amongst other features,'is provided novel means for effecting a positive retraction of the hydraulic ram after a power stroke.

Valveless hydraulic apparatus according to this invention comprises two co-aXial cyl-l inders of different bore arranged inv prolon ation of, and freely open to each other, tol orm a common space for the hydraulic Huid, a liquid-tight rram operating within the larger bore, 'a liquid tight plunger operating within the smaller bore, means for positively retracting the ram Vafterr a working stroke, and means for reciprocating said plunger! Details of the construction and operation of my improved hydraulic press will be more fullyv described with reference to the drawings '.,which illustrate by way ofexample, only a valveless hydraulic press according to my invention applied' to a punching machine, although it Yis to' be understood that i my Ivalveless hydraulic press apparatus may be employed in connection with any machine or for any purpose to which such press may be applicable.

' `ig. `l -is a view in side elevation partly in section 0n the line 1 1 of Fig. 2V of a punchingmachine according to my present invention with the lever vpulled'fu'lly down and the plunger and the ram at the extreme end of the downward'punching stroke.

lFig. 2 is an end elevation of Fig. l partly in section on the line 2 2 of Fig. l. i Fig. Y3 is aside'elevation partly in section of an alternative construction according to my present invention the various modifica- 1922, seria1n0.5e2,o5o.

tions in which will be hereinafter described in detail. i

Fig. 4 shows a local longitudinal section through the ram cylinder illustrating anv alternative construction of the ram inwhich the upper surface thereof is vrecessed or cut away in suchwise as to produce an obturating effect on the upper outer circumferenceof the ram when pressure is applied, thereby to prevent leakage of -oil past the ram.

InFigs.1and2:- I

A'is the cylinder of differential bore, A1 that portion of the cylinder in which the ram B is adapted to be reciprocatedthis said cylinder A1 being hereinafter referred toas the ram cylinder.7

A2 is thesmallerbored portion ofthe cylinder A provided at its upper end with a gland A3 and designed to receive the plunger C tofbe vreciprocated therein said plunger C being provided at its lower end with an hydraulic cup ring C1, the upper end of the plunger C being closed by a lead washer C2 over which latter a metal capis screwed down.

The bushing C4 screwed intofthe `lower end of the plunger C provides a seating or stop for the enlarged head D1 oftheram withdrawing rod D, the lower end of which latter is screwed into the top of the Aram B.

The ram B is cut away to provide an oil space E and is provided'withan hydraulic cup ring F to make a. tight lit with the ram cylinder A1. z

A filling hole El is provided4 in thelram cylinder A1 for the admission of oil or other desired fluid and is closed bythe screwthreaded cap E2 (see 'Fig 2).'

A. set screw B1 fitting in lthe longitudinal slot or recess B2 in the ram B is Sclewed through the cylinder A1 to prevent rotation of the ram B when in use (see Fig. 2).

The ram B is recessed in the underside for the reception of the punch G and a set screw G1 is screwed transversely' into the ram B to hold the punch or other desired tool in position a recess G2 being provided in the shank of the punch `for the purpose of receiving the end of the set screw G1.

A stripper plate H is mounted lon the rod H1 by means of the locking screw H2 and the rod H1 being 'fixed at its upper end to the ram cylinder body7 A its forked ends embracing the punch G for the purpose of stripping therefrom the work-piece when the punch is returning to normal position after a punching operation.

The cylinder A is formed with a lateral extension A* adapted to be received in a recess J2 in the upwardly extending bracket J1 of the base J of the machine, this projecting portion A4 being centrally bored and internally screw-threaded to receive a corresponding screw-threaded fixing bolt K.

A die-plate L is provided with a series or holes or openings therethrough of dill'erent sizes (or/and if desired of dierent shapes) arranged equidistant from a common centre on said plate; and this die-plate L is mounted or carried on a central pin or spindle L1 adapted to be revolvably mounted in a suitable recess J4 in the base d.

The die plate L is mounted eccentrically with respect to the punch Gf on the ram B so that whatever sized o-r shaped punch may be mounted on the ram the die-plate can be revolved to bring the corresponding hole below said punch and then y the die-plate locked in this position by tightening set screws (not shown) in the transverse screwthreaded borings J2 J in the base J.

The lever N is pivotally attached to the metal cross-head C3 on the plunger C and is also pivotally attached at M2 to the links M which in turn are pivotally mounted at ll/l1 on the bracket J1, the whole being so arranged and proportioned that the thrust on the plunger C- is purely vertical when the lever N is operated.

Fig. 3 illustrates an alternative construction wherein a cylindrical metal sleeve 0 is iixedly mounted on or formed integral with the bracket J1, this sleeve C being internally screw-threaded for a portion of its length and adapted to receive the ram cylinder A1 which is correspondingly screw-threaded eX- ternally, the whole hydraulic mechanism being thereby capable of vertical adjustment relative to the base of the machine.

i-rn internally screw-threaded locking ring P is provided vto lock the cylinder A1 in any position to which it has been so adjusted.

ln this construction the plunger cylinder :l2 is extended downwardly into the ram cylinder AJ and the top of the ram is centrally recessed or cut away, if desired.

F ig. 4 illustrates a modified construction ci? the ram B the upper portion of which in rthis case is recessed or cut away in suchwise as to leave a relatively thin and upwardly tapering wall B1 tor the purpose o'l" producing an obturating eflect in the ram cylinder when pressure is applied, thereby to assist in ensuring against leakage o:tl oil past the ram in operation.

The operation is as follows When the lever N2 N is pulled down the plunger C is thereby forced downwardly in the plunger cylinder A2 forcing the oil or other liquid therein into the oil space l in neiaace the larger part A1 or" the cylinder which is already quite full oli' liquid, the ram D carrying the punch G or other tool being 'thereby powerfully driven down towards the work-piece.

The lever N2 N is designed according to the leverage required, iA e. to the power to transmitted to the plunger' C; and the length of travel to be imparted to the plunger C also designe-l according to the '2 stroke or travel to be thereby imparted to the ram D. e. g. with a leverage of l0 to l exerted on the plunger C and the area ot lthe end of the plung r C one-tenth the area of the ram B, then with a l00 lb. pull at the end of Vthe lever N2 N a pressure of approximately l0,000 lbs. would be exerted on the punch G or other tool lined to the ram.

lli/Then the punching or other action has been el'iected the lever N2 N is drawn back until the enlarged head end D1 ol the ram withdrawing rod D is engaged by the seati' formed by the bushing C4 in the bore of the plunger C and upon the lever being returned to normal position the ram withdrawing rod D is thereby carried upwardly bringing back into normal position the ram to which the lower end of the ram withdrawing rod D is lined at the same time strippi. g work-piece `from the tool ready for the next punching or other operation.

rllie diameter of the enlarged head D" ol the ram withdrawing rod D is smaller than the diameter of the bore of the plunger C to thus permit the passage of the oil past this head D1 during relative movement of said plunger C and rod D; while the said rod D where it passes through the lowerend of said plunger C makes only a loose fit with said lower end or the interior wall of the bushing CL-through which the rod D slides-#may be provided with vertical grooves or channels, so as to allow the passage of oil between the interiorot the plunger C and the oil space E.

A recess J4 is provided in the base J for withdrawing the punchings or cuttings or permitting them to drop; said slot J4 being vertically disposed in said iXed base J and extending from the interior of theside wall to the centre of the seating for the die-plate L or other work-piece support, in suchwise that a pin or stud centrally fixed on the under surface of the die-plate orthe support for the work-piece may be yslid along and completely out of said slot thereby to remove the die-plate or work-piece support.

Vf hen it is desired to alter the diameter of the punch it is only necessary to slacken the screws J2 holding the work-piece support in position, revolve the support (such as the die-plate L hereinbefore described) until the hole of the desired diameter is directly under the punch Gr and again tighten the screws J3; the screw l-l2retaining the stripper plate H is then loosened, the stripl lOO per plate removed and a punch of the required size substituted in the ram head and the stripper plate H then re-xed.

It is understood that the valveless hydraulic mechanism according to my present invention which I have herein described and illustrated as applied to a punching tool may be employed in conjunction with any other tool or machine to which it is or may 1 be applicable.

F or example it is applicable to and may advantageously be employed in suoli processes as shearing, cropping, rivetting, embossing, piercing7 bar straightening and the 1 like.

What I claim is l. Valveless hydraulic apparatus comprising two co-axial cylinders of different bore, arranged in prolongation of, and freely open to, each other to form a common space for the hydraulic fluid, a. liquid-tight ram operating within the larger bore, a hollow liquid-tight plunger operating within the smaller bore, means arranged within and co-operating with said plunger for positively retracting the ram and means for reciprocating said plunger.

2. Valveless hydraulic apparatus comprising two co-axial cylinders of diflerent bore', arranged in prolongation of, and freely open to, each other to form a common space for the hydraulic fluid, a liquid-tight ram operating within the larger bore7 a hollow liquidtight plunger operating within the smalle-r bore, a shoulder formed withinv the lower arranged in prolongation of, and freely open to, each other to iorm a common space for the hydraulic luid, a liquid-tight ram operating within the larger bore, a hollow liquid-tight plunger operating within the smaller bore, a shoulder' Jformed within the lower end of said plunger, a `ram-retracting device comprising an inextensible member attached at one end to the ram and having an enlargement sliding loosely within said'` hollow plunger and adapted to be engaged by the shoulder within said plunger towards the end of the return stro-ke of the latter, and a system of levers connected to said plunger and to the base of the apparatus in suchwise as to exert axial thrust upon said plunger to actuate the same.

ERIC MONTAGUE SMITH. 

